A gyratory crusher construction which bears the closest resemblance to the one to be described in this specification is disclosed in USSR Inventor's Certificate No. 578,098; IPC B 02 C 2/04, published 1978. This prior art crusher comprises a housing having arranged therein an adjustment ring which in turn accommodates a crushing cone with a bearing spherical surface and a shaft press fitted thereinto, an upper support of the crushing cone which is disposed in a cross-piece of the adjustment ring and includes a detachable insert with a ball joint, the interior of the ball joint receiving an upper end of the crushing cone shaft; the device further comprises a cup member adapted to underlie the crushing cone coaxially with the housing, a thrust element having a spherical surface secured on the bearing surface of the cup member and mating with the bearing spherical surface of the crushing cone, an eccentric arranged on a lower shank of the crushing cone shaft, and a drive means for rotating the eccentric. In order to prevent destabilization of the crushing cone, the crusher is provided with the ball joint and a means for vertical displacement thereof, whereas the cone shaft projects from the upper part of the crushing cone, the ball joint being mounted on this projecting portion of the shaft at a distance from the spherical surface of the thrust element equal to the radius of its sphere. In other words, the upper support of the crushing cone serves for preventing destabilization of the crushing cone or displacement thereof from the thrust element of the support cup member.
This known gyratory crusher construction requires a very high accuracy during installation of the ball joint at a distance from the spherical surface of the thrust element equal to the radius of its sphere, i.e. it is necessary to align the centers of sphere of the spherical support of the thrust element with that of the ball joint, because the failure to align these centers results in a loss of stable movement of the crushing cone to cause excessive wear of the thrust element on the edges of its spherical surface.
The centers of the ball joint sphere and the sphere of the spherical surface of the thrust element must be aligned both in the direction perpendicular to the axis of the crusher (for providing coaxiality of the ball joint with the sphere of the spherical surface of the thrust element), and in the longitudinal direction (in height). Coaxiality requires high manufacturing precision during fabrication of the parts and components of the crusher. In contrast, for aligning the centers of these spheres vertically, use is normally made of specially designed devices which require high labour expenditures, especially during spacing of the ball joint at a distance equal to the radius of sphere of the spherical surface of the thrust element, which makes assembly of the crusher a rather complicated and time consuming affair. In addition, the spherical insert with the ball joint arranged in the hole of the cross-piece of the adjustment ring and capable of displacement axially of this hole during crusher operation tends to damage the surface of this hole in the cross-piece to render the upper support of the crushing cone less reliable and consequently affect the overall reliability of the gyratory crusher.